Diastereo- and Enantiomerically Pure Allylboronates: Their Synthesis and Scope.
May 1st, 2008 | by admin |Diastereo- and Enantiomerically Pure Allylboronates: Their Synthesis and Scope.
Allylboronates are highly attractive reagents for allyl additions. Enantiomerically pure, stable reagents with a stereogenic centre in alpha-position to boron are especially versatile, albeit often difficult to synthesize. Starting from boron-containing allyl alcohols 6 and 7, which are discussed in detail herein, a set of reagents were obtained via [3,3]-sigmatropic rearrangements and consecutive transformations in the side chain. The configurations could be established first by chemical correlation, but also by X-ray crystallography (16, 18, 34, and 39). Allyl additions were performed resulting in the formation of predominantly (Z)-configured homoallylic alcohols (31, 43-45) with high enantiomeric excess. Detailed investigations on the matched-mismatched interaction between the reagents 15/16 (and ent-15/ent-16, respectively) and isopropylidene glyceraldehyde 42 d are presented.
Pietruszka J, Schöne N, Frey W, Grundl L.
Institut für Bioorganische Chemie der Heinrich-Heine-Universität Düsseldorf im Forschungszentrum Jülich, Stetternicher Forst, Geb. 15.8, 52426 Jülich, Germany, Fax: (+49) 2461-616196.